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参数资料
| 型号： | HSMS-270P-BLKG |
| 元件分类： | 参考电压二极管 |
| 英文描述： | UNIDIRECTIONAL, 4 ELEMENT, SILICON, TVS DIODE |
| 封装： | ROHS COMPLIANT, SC-70, 6 PIN |
| 文件页数： | 7/9页 |
| 文件大小： | 125K |
| 代理商： | HSMS-270P-BLKG |
7
Applications Information
Schottky Diode Fundamentals
The HSMS-270x series of clipping/clamping diodes
are Schottky devices. A Schottky device is a rectifying,
metal-semiconductor contact formed between a metal
and an n-doped or a p-doped semiconductor. When a
metal-semiconductor junction is formed, free electrons
ow across the junction from the semiconductor and ll
the free-energy states in the metal. This ow of electrons
creates a depletion or potential across the junction. The
dierence in energy levels between semiconductor and
metal is called a Schottky barrier.
P-doped, Schottky-barrier diodes excel at applications
requiring ultra low turn-on voltage (such as zero-biased
RF detectors). But their very low, breakdown-voltage
and high series-resistance make them unsuitable for
the clipping and clamping applications involving high
forward currents and high reverse voltages. Therefore,
this discussion will focus entirely on n-doped Schottky
diodes.
Under a forward bias (metal connected to positive in an
n-doped Schottky), or forward voltage, VF, there are many
electrons with enough thermal energy to cross the barrier
potential into the metal. Once the applied bias exceeds
the built-in potential of the junction, the forward current,
IF, will increase rapidly as VF increases.
When the Schottky diode is reverse biased, the potential
barrier for electrons becomes large; hence, there is a
small probability that an electron will have sucient
thermal energy to cross the junction. The reverse leakage
current will be in the nanoampere to microampere range,
depending upon the diode type, the reverse voltage, and
the temperature.
In contrast to a conventional p-n junction, current in
the Schottky diode is carried only by majority carriers
(electrons). Because no minority-carrier (hole) charge
storage eects are present, Schottky diodes have carrier
lifetimes of less than 100 ps. This extremely fast switching
time makes the Schottky diode an ideal rectier at fre-
quencies of 50 GHz and higher.
Another signicant dierence between Schottky and p-n
diodes is the forward voltage drop. Schottky diodes have
a threshold of typically 0.3 V in comparison to that of 0.6 V
in p-n junction diodes. See Figure 6.
Through the careful manipulation of the diameter of the
Schottky contact and the choice of metal deposited on
the n-doped silicon, the important characteristics of the
diode (junction capacitance, CJ; parasitic series resistance,
RS; breakdown voltage, VBR; and forward voltage, VF,)
can be optimized for specic applications. The HSMS-
270x series and HBAT-540x series of diodes are a case in
point.
Both diodes have similar barrier heights; and this is
indicated by corresponding values of saturation current,
IS. Yet, dierent contact diameters and epitaxial-layer
thickness result in very dierent values of CJ and RS. This
is seen by comparing their SPICE parameters in Table 1.
Table 1. HSMS-270x and HBAT-540x SPICE Parameters.
Parameter
HSMS- 270x
HBAT- 540x
BV
25 V
40 V
CJ0
6.7 pF
3.0 pF
EG
0.55 eV
IBV
10E-4 A
IS
1.4E-7 A
1.0E-7 A
N
1.04
1.0
RS
0.65 Ω
2.4 Ω
PB
0.6 V
PT
2
M
0.5
At low values of IF ≤ 1 mA, the forward voltages of the
two diodes are nearly identical. However, as current rises
above 10 mA, the lower series resistance of the HSMS-
270x allows for a much lower forward voltage. This gives
the HSMS-270x a much higher current handling capabil-
ity. The trade-o is a higher value of junction capacitance.
The forward voltage and current plots illustrate the
dierences in these two Schottky diodes, as shown in
Figure 7.
PN
CURRENT
0.6 V
+
–
BIAS VOLTAGE
PN JUNCTION
CAPACITANCE
METAL N
CURRENT
0.3V
+
–
BIAS VOLTAGE
SCHOTTKY JUNCTION
CAPACITANCE
I F
–
FORWARD
CURRENT
(mA)
VF – FORWARD VOLTAGE (V)
.01
10
1
.1
300
100
0
0.1
0.3
0.2
0.5
0.4
0.6
HSMS-270x
HBAT-540x
Figure 6.
Figure 7. Forward Current vs. Forward Voltage at 25°C.
相关PDF资料 |
PDF描述 |
|---|---|
| HSMS-2800-TR2 | SILICON, MIXER DIODE |
| HSMS-280E-BLKG | SILICON, MIXER DIODE |
| HSMS-2805L31 | SILICON, MIXER DIODE |
| HSMS-2803L31 | SILICON, MIXER DIODE |
| HSMS-2862L31 | SILICON, MIXER DIODE |
相关代理商/技术参数 |
参数描述 |
|---|---|
| HSMS-270P-TR1G | 功能描述:肖特基二极管与整流器 15 VBR 6.7 pF RoHS:否 制造商:Skyworks Solutions, Inc. 产品:Schottky Diodes 峰值反向电压:2 V 正向连续电流:50 mA 最大浪涌电流: 配置:Crossover Quad 恢复时间: 正向电压下降:370 mV 最大反向漏泄电流: 最大功率耗散:75 mW 工作温度范围:- 65 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:SOT-143 封装:Reel |
| HSMS-270P-TR2G | 功能描述:肖特基二极管与整流器 15 VBR 6.7 pF RoHS:否 制造商:Skyworks Solutions, Inc. 产品:Schottky Diodes 峰值反向电压:2 V 正向连续电流:50 mA 最大浪涌电流: 配置:Crossover Quad 恢复时间: 正向电压下降:370 mV 最大反向漏泄电流: 最大功率耗散:75 mW 工作温度范围:- 65 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:SOT-143 封装:Reel |
| HSMS-2800 | 制造商:Avago Technologies 功能描述:DIODE SCHOTTKY RF SOT23 |
| HSMS-2800#L31 | 制造商:Avago Technologies 功能描述:Rectifier Diode, Schottky, 70 Volt, SOT-23 |
| HSMS-2800-BLKG | 功能描述:肖特基二极管与整流器 70 VBR 2 pF RoHS:否 制造商:Skyworks Solutions, Inc. 产品:Schottky Diodes 峰值反向电压:2 V 正向连续电流:50 mA 最大浪涌电流: 配置:Crossover Quad 恢复时间: 正向电压下降:370 mV 最大反向漏泄电流: 最大功率耗散:75 mW 工作温度范围:- 65 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:SOT-143 封装:Reel |
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